The present invention relates to an improved methods and devices for treating and healing a tissue deficiency or pathology in a living human or animal body. The methods and the devices combine a mechanical action and a biological action.
For example, the present invention can be used for guided bone regeneration in the jaws as part of dental treatment with dental implants. It can be used to fixate bones, to fill bone cavities and to expand bone cavities.
The present invention consists of an expansion device that can include a bioresorbable film or a perforated film and a method for tissue regeneration. In order to clarify the principles of the present invention the following description will focus on two implementations: bone regeneration in the jaws preceding dental treatment with dental implants, and fixating bone fractures. The same principles may be applied to other tissues and other organs and other areas of the body.
Treatment of edentulous patients with osseointegrated fixtures made of titanium is a well known procedure in the art. The procedure includes installing a fixture in the alveolar bone of an at least partially edentulous jaw. Usually several months are required for proper healing after fixture installation.
After healing, an abutment is installed on the upper portion of the fixture. After several weeks, an artificial tooth may be mounted on the abutment and the procedure is complete.
Installation of implants requires sufficient alveolar bone, generally about 10 mm height and 6 mm width.
When a tooth is removed, the alveolar bone is gradually resorbed because of the absence of stimulus of ossification-inducing pressure from the teeth. As the resorption process advances, the size of the bone gets reduced, i.e. the bone on which the dental roots are positioned—the alveolar ridge starts shrinking.
The absence of just one tooth can cause modifications throughout the dental arch and even prompt a possible softening (loss of insertion) which may cause the loss of other teeth. The absence of several teeth aggravates the problem. Bone loss may finally modify the patient's appearance and, depending on the loss, may make him incapable of receiving bridges, implants or even dentures.
It is then necessary to carry out several surgical operations to reconstruct the alveolar ridge of the maxilla or mandible.
Although these methods of surgical reconstruction have been successfully performed, this type of operation has had drawbacks. Certain methods have involved opening the mucoperiosteal tissue along the entire length of the atrophic alveolar ridge and then placing a bone graft material and a membrane on top of the graft and then suturing the delicate mucoperiosteal tissue back together to cover the membrane. The role of the membrane is to maintain the bone graft in its place and to prevent the mucoepithelium from growing into the graft and interfering with the process of bone regeneration. This surgical operation has had drawbacks because it is difficult to stretch and cover the augmented ridge resulting in high prevalence of membrane exposure and infection.
The present invention is unique because it simultaneously regenerates the soft and the hard tissues, therefore avoids most of the foregoing drawbacks and permits a more simplified and effective means for bone regeneration:
This invention relates also to methods and devices for correcting bone abnormalities and involves use of an inflatable device, which can be inserted into a prepared cavity in bone or to be adjacent bones. The device is inflated using bone replacement material to expand and fill the cavity. The device can be inserted subperiostealy to enlarge the bone.
U.S. Pat. Nos. 5,108,404 and 4,969,888 to Scholten et al. describe a system for fixing osteoporotic bone using an inflatable balloon, which compacts the bone to form a cavity into which bone cement is injected after the balloon is withdrawn. The invention requires the use of fluoroscopy to monitor the injection and to help guard against cement leakage through fissures in bone. Unfortunately, such leakage is known to occur in spite of these precautions. Since such leakage may cause serious injury, including paralysis, an improved device and method is needed. U.S. Pat. No. 5,972,015 to Scribner et al. describes a system of deploying a catheter tube into the interior of a vertebra and expanding a specially configured nonporous balloon there within to compact cancellous bone to form a cavity. The Scribner U.S. Pat. No. 5,972,015 approach utilizes a non-porous balloon which is inflated within the bone to cause compression. The cavity thus formed may then be filled with bone cement. Unfortunately, the bag used by Scribner may be ruptured during expansion to compact cancellous bone due to sharp projections found within the cavity to be expanded. Filling the cavity eventually formed could allow leakage of bone cement out of the bone against vessels or nerves which may cause undesirable complications.
U.S. Pat. Nos. 5,549,679 and 5,571,189 to Kuslich describe a device and method for stabilizing the spinal segment with an expandable, porous fabric implant for insertion into the interior of a reamed out disc which is packed with material to facilitate bony fusion. The device of Kuslich prevents direct contact between the filled material and the bone. In the present invention, an improved device is used to correct bone abnormalities including, but not limited to, bone tumors and cysts, tibial plateau fractures, avascular necrosis of the femoral head and compression fractures of the spine.
The present invention involves an improvement of all of the previous techniques and avoids complications that could occur with the system of U.S. Pat. No. 5,972,015. Therefore, it is an object of this invention to provide a method and apparatus that has some or all of these properties.